1. Field of the Invention
The present invention pertains to connector apparatus for joining elongated members, in particular conduits or pipes. More specifically, it pertains to connector apparatus suitable for connecting non-axially aligned pipes and conduits in particularly difficult environments, such as in submarine installations.
2. Description of the Prior Art
There are, of course, many connector devices for joining the ends of two conduits or for coupling a conduit to the outlet of an apparatus. One general type of connector utilizes a ball and socket joint, in which the male portion is attached to one conduit and the female to the other conduit. The male is received within the female portion and some means is provided for holding the two portions together.
Some connectors of the ball and socket joint type have been developed for submarine installation. Such connectors have been used for providing a flexible joint to connect a marine riser or conduit to a submarine wellhead, thus providing communication between the submarine wellhead and a marine drilling platform. In many of these connectors, the ball is latched into the female socket by a resilient collar which is radially deformable and maintained in a compressed state by an annular piston of a hydraulic jack or other similar devices. Such flexible connectors permit some degree of relative rotary and bending movement between the coupled conduits. For the submarine wellhead and riser type installations, this is desirable. Examples of such connectors may be seen in U.S. Pat. Nos. 3,333,870; 3,450,421; and 3,695,633.
The flexible connector designs for wellhead riser installations are not suitable for connecting pipes in a high pressure circulating fluid pipeline which may lie for prolonged periods on the sea floor. In such applications, where ball and socket type connectors have recently been used, the resilient collar is replaced by a locking system which grips the ball with sufficient force to prevent it from turning. In this way, the connected conduits become a fixed unit with good mechanical continuity capable of withstanding the strong forces and stresses existing in pipelines.
Like the submarine wellhead-riser connectors of the prior art, the ball and joint connectors now being used for joining pipelines utilize some form of hydraulic jack or mechanism for locking. The locking system may comprise a plurality of jaws forming a gripping assembly which is activated by radial hydraulic jacks or an annular piston of a hydraulic jack. Such a pipeline connector may be seen in U.S. Pat. No. 3,874,706.
Since these ball and joint connectors of the prior art utilize hydraulic mechanisms, it is necessary to use a compressed fluid to maneuver the locking mechanism, meaning that such connectors are not autonomous. They are useful for installations situated near a platform which supports a central hydraulic system to feed the hydraulic mechanism, but they are poorly adapted for fitting in a pipeline which may stretch for some length along the sea floor and where they may be inaccessible to a central hydraulic system.
In order to overcome the limitations represented by the necessity of permanently feeding hydraulic mechanisms after the locking system has fixed onto the ball, the compressed fluid is sometimes replaced by a polymerizable resin which hardens within the connector and keeps it fixed in the locked position. However, such a method of fixing the locking system has the disadvantage of being irreversible, preventing uncoupling and replacement of malfunctioning components.